Exam qs Flashcards
Similarities and differences of tRNA and mRNA?
mRNA doesn’t have hydrogen bonds, tRNA does
mRNA doesn’t have an amino acid binding site, tRNA does
mRNA has more nucleotides
différent mRNAs have different lengths, tRNAs have similar lengths
How translation leads to the production of a polypeptide (starting with mRNA in the cytoplasm)
mRNA binds to ribosome,
Ribosome moves to the start codon,
tRNA brings an amino acid,
anticodon on tRNA is complimentary to the codon on mRNA,
Ribosome moves along to the next codon,
Amino acids are joined by peptide bonds (undergo condensation reaction)
What is the proteome of a cell?
All the different proteins produced by a cell.
Describe the role of a ribosome in the production of a polypeptide?
mRNA binds to the ribosome,
Idea of 2 codons,
allows the tRNA with anti codons to bind,
Catalyses the formation of peptide bonds between amino acids
Ribosome moves along mRNA to the next codon
In a eukaryotic cell, the base sequence of the mRNA might be different from the sequence of pre-mRNA, why?
mRNA hasn’t been spliced yet so still contains introns and exons.
Explain how the organic bases help to stabilise the structure of DNA?
Many hydrogen bonds provide a lot of strength
The hydrogen bonds between the base pairs hold together the two strands of DNA
Two proteins have the same number and type of amino acids but different tertiary structures, why?
The sequence of amino acids is different so the primary structure is different.
This means that disulfide bonds form in different places.
Describe the structure of proteins?
- Polymer of amino acids
- amino acids joined by peptide bonds which are
- formed by condensation reactions
- primary structure is the order of amino acids
- secondary structure is the folding of the polypeptide chain due to hydrogen bonds
- tertiary structure is the secondary structure further folding to form a 3D structure due to hydrogen and ionic and disulfide bonds
- quaternary structure is multiple polypeptide chains
Explain how formation of an ES complex increases the rate of reaction?
When an ES complex forms the active site changes shape as it moulds around the substrate, this puts pressure on the substrate causing its hydrogen and ionic bonds to become distorted (weakening them) so less energy is required to break them, and activation energy is reduced.
When x (in this case, ATR ) phosphorylates other enzymes, these enzymes become able to bind to their substrates. Why?
Because ATR changes the shape of the enzyme’s tertiary structure which changes the shape of the active site so that it becomes complimentary to the substrate.
Suggest how the acidic conditions created by osteoclasts cause the inactive form of the protein osteocalcin to change into the active form of osteocalcin?
The change in pH breaks the hydrogen and ionic bonds which changes the tertiary structure. (Then the tertiary structure becomes complimentary to the substrate so osteocalcin becomes active)
[graph showing the enzyme activity in washing powder over time at 50 degrees (less steep negative gradient going down) compared to 60 degrees (really steep negative gradient going down)]
- both denatured
- denaturation at 60 degrees is faster because there’s more kinetic energy
- at the high temperatures the ionic and hydrogen bonds are broken
- this causes the tertiary structure to change shape so that it’s no longer complimentary with the substrate
Experiment adding different concentrations of lipase to lipids to see how the concentration affects the lipids hydrolysis…. what is the control?
Boiled lipase solution
ADP + Pi goes to ?
ATP + H2O
An antibiotic inhibits bacterial ATP synthase enzyme but not human ATP synthase enzyme, why?
Human ATP synthase has a different active site to bacterial ATP synthase (so the antibiotic isn’t complimentary to the active site of the human ATP synthase which means they don’t bind and the reaction ISN’t stopped)
Give two ways ATP is a suitable energy source in cells?
- releases small amounts of energy
- it can be synthesised quickly (because it only takes a single reaction for it to be broken down)
Which biological processes involve electron transport chains?
Photosynthesis
Aerobic respiration
In which biological processes is ATP produced?
Photosynthesis
Anaerobic respiration
Aerobic respiration
Which biological processes occur in organelles?
Photosynthesis
Aerobic respiration
Gland cells produce and secrete breast milk which contains a high concentration of protein.Explain why there are many mitochondria and Golgi vesicles in gland cells.
Many mitochondria mean lots of ATP is produced for active transport.
Many Golgi vesicles to transport the milk proteins out of the cell